The field of this invention is that of non-contacting position sensors for use in control systems and the like. The invention particularly relates to an inductive position sensor and to an automotive control system using the inductive sensor for regulating operating parameters of the automobile in accordance with movement of an automotive member.
Many different types of non-contacting position sensors have been proposed for use in various different types of control systems for detecting the relative position of an object. Such sensing means are commonly arranged to provide output signals which are in some way representative of the object position and such outputs have typically been utilized for regulating some aspect of the control system. However, the sensor means have often been expensive, have tended to require special adaptation for each different type of use, and have frequently had operating characteristics which have prevented their use in automotive environments and the like. It is now proposed that various electronic controls utilizing microprocessors and the like be provided for regulating the operation of automobile engines and other automobile systems. For this purpose, it has been proposed that various types of position sensing means be arranged to provide inputs to the electronic controls representative of the position of the engine distributor or the crankshaft or the like.
In this regard, Hall effect position sensing means have been arranged relative to the engine distributor for providing a control signal to such microprocessor means representative of the instantaneous rotational position of the distributor during engine operation. The same Hall effect means have also been proposed for sensing the instantaneous position of rotation of the engine crankshaft. It has also been proposed that such Hall effect sensors be arranged in a fluid-adjustable shock absorber system to sense the shock-absorber position under load for regulating fluid supply to restore desired shock-absorber levels. Such Hall effect sensors are expensive. They appear to be somewhat unreliable for use in automotive environments.
In this regard, Hall effect position sensing means have been arranged for providing a control signal to such microprocessor means to be representative of the instantaneous rotational position of an engine distributor during automotive engine operation. Alternately, sensors incorporating a permanent magnet and a coil have been used for sensing the rotational position of an engine distributor or crankshaft or the like, the coupling between the magnet and coil being varied by rotating a ferromagnetic cam. Hall effect sensors tend to be expensive and appear to be somewhat unreliable for use in automotive environments; the coil-permanent magnet sensors also tend to provide outputs which vary somewhat depending on the speed of rotation of the cam so that substantial tolerances are required; and any sensor incorporating a permanent magnet tends to accumulate magnetic dust particles and the like.
It is an object of this invention to provide a novel and improved non-contacting inductive position sensor; to provide such a sensor which is inexpensive to manufacture, which is conveniently mounted for use in determining position of an object, which is accurate and reliable in use, which provides an output independent of the rate of change of position of the object whose position is being monitored, and which is adapted for use in automotive environments and the like. It is also an object of this invention to provide control systems for regulating operation of the system in accordance with movement of an object; to provide such a controlsystem which reulates an operating aparameter of an automotive engine in response to change in position of a distributor or crankshaft as sensed by the said non-contacting inductive position sensing means; and to provide a control which regulates fluid supply to a fluid-adjustable shock absorber system in accordance with change in position of shock-absorbers in the system as sensed by said non-contacting inductive position sensing means.